Connection to bellsouth email failing

Several attempts to contact the bellsouth/yahoo/att email servers are failing.  Support is no help..They have no clue about any issues and keep telling me it's a password or browser issue...  I check email from my phone... Browser only came into play because I tried logging in there as well and was presented with an ID or PASSWORD failure... What gives???  I have made no changes to my phone so this should NOT be a password issue...